JP2001035248A - Conductivity imparting particle and anisotropically conductive adhesive using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide conductivity-imparting particles used for electrical connection between an LCD(liquid crystal display) or a PDP(plasma display) and a circuit board mounted with its drive circuit and to provide an anisotropically conductive adhesive using the same. SOLUTION: This conductivity-imparting particles A are made by covering surfaces of conductive particles 1 with an insulating resin 2, and the conductive particles 1 are made by applying metal plating 13 to surfaces of acrylic resin particles each comprising a flexible nucleus 11, and a shell 12 harder than the nucleus and coating the nucleus 11. The anisotropically conductive adhesive B is made by dispersing the conductivity-imparting particles A in an insulating adhesive 3. The anisotropically conductive adhesive is low in initial connection resistance, superior in reliability of connection over a long period of time, and moreover superior in short circuit (leakage) prevention.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LCD (Liquid C
The present invention relates to a conductivity-imparting particle used for electrical connection or the like between a crystal display (PDP) or a PDP (Plasma Display) and a circuit board on which the driving circuit is mounted, and an anisotropic conductive adhesive using the same. The term “adhesion” described in the present specification includes the concept of adhesion,
"Adhesive" includes the concept of an adhesive.

[0002]

2. Description of the Related Art Conventionally, an anisotropic conductive adhesive is used for a display such as an LCD or a PDP and a printed circuit board (PCB).
d), connection with FPC (Flexible Printed Circuit),
Alternatively, it is used for connection between a PCB and an FPC. This anisotropic conductive adhesive is obtained by dispersing conductive particles in an insulating adhesive.Examples of the conductive particles include furnace black, channel black, carbon black such as acetylene black, and graphite. Carbon-based particles, metal particles such as gold, silver, copper, and nickel aluminum, and plastic-based particles whose surfaces are plated with metal are used. Further, with the recent increase in precision of electronic devices, the connection pitch has become extremely small, and the density of particles has been increasing.

[0003] However, among these conductive particles, pressure (5 to 5) such as metal particles and carbon-based particles is used.
100 kgf / cm ^2, usually those that hardly deformed by 20~40kgf / cm ^2), heating during thermocompression bonding can not easily follow the displacement of the physical properties of the insulating adhesive by pressure, various post-connection Under the use environment, the microscopic movement due to the residual stress of the insulating adhesive causes partial conduction failure, high resistance value, etc., which has a serious adverse effect on the long-term reliability of the electrical connection. I have. Therefore, in order to eliminate these adverse effects and the like, conductive particles whose core is plastic-based particles which are more easily deformed than metal particles or carbon-based particles and whose surface is plated with metal have been used.

The conductive particles using the plastic particles as nuclei make surface contact with the adherend in a state of thermocompression bonding. The larger the contact area, the lower the contact resistance and the more stable the particles. The higher the resilience of the particles, the higher the contact pressure with the adherend and the lower the contact resistance. However, the contact area was contradictory such that the softer the core of the plastic, the larger the hardness, and the stronger the resilience, the stronger the core. In other words, when the conductive particles are made flexible to increase the contact area, the conductive particles tend to be plastically deformed, and since they do not have elasticity, the restoration rate is reduced. Conversely, when the particles are hard, the restoration rate is increased, and the contact pressure is increased. There is a problem in that the contact area is small, but the contact area is close to a point contact, but in both cases, the long-term reliability of the electrical connection is lacking. Furthermore, as described above, with the recent miniaturization and high precision of electronic devices, the connection pitch has become extremely small, and the density of conductive particles has been increasing. There is also a problem of short circuit (leak).

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and aims to solve the problem.
In particular, conductivity-imparting particles which reliably and reliably maintain electrical connection even by temperature / humidity cycles and thermal shock, and also improve insulation between adjacent terminals, and anisotropically conductive bonding using the same. It is intended to provide an agent.

[0006]

As a result of various studies on means for solving the above-mentioned problems of the prior art, the present inventor has found that a core (core) and a shell (shell) are provided so that conductive particles have three functions. In addition, the contact area is increased by the flexible core, the restoration rate is provided by the hard shell, and the insulation is maintained by the insulating film, thereby improving the reliability of the electrical connection. It has been found that the stability in temperature and humidity cycles and thermal shock is improved, and that the insulation properties are also excellent, and the types, hardness, thickness,
By further research on thermal properties, etc.,
The present invention has been completed. That is, the present invention resides in the following (1) to (3). (1) The surface of the synthetic resin-based particles comprising a core having flexibility and a shell harder than the core covering the core is coated with an insulating resin. Conductivity imparting particles characterized by being covered. (2) The 10% compressive strength of the conductive particles is 0.2 to 5.0 kg / m.
m ² and a restoration rate of 5 to 90%. (3) An anisotropic conductive adhesive obtained by dispersing the conductive particles according to the above (1) or (2) in an insulating adhesive.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an example of the embodiment of the conductivity-imparting particles of the present invention.
The conductivity-imparting particles A of the present embodiment are, as shown in FIG.
The surface of the synthetic resin-based particles composed of a core 11 having flexibility and a shell 12 harder than the core which covers the core 11 is coated with metal plating 13 so that the surface of the conductive particles 1 is further insulated. It is covered with resin 2.

The core 1 of the conductive particles A constituting the present invention
1. Examples of the material of the shell 12 include styrene-based, silicone-based, urethane-based, divinylbenzene-based, benzoguanamine-based, melamine-based, and phenol-based resins. ), The hardness of the resin component used for the shell 12 is added by adding a degree of polymerization and / or an additive so that the core 11 and the shell 12 do not undergo interface delamination during thermocompression bonding or subsequent thermal shock. It is desirable to change and include, especially,
Both the core 11 and the shell 12 are preferably made of an acrylic resin having excellent heat resistance, easy hardness adjustment, and easy suspension polymerization. Of course, different resin-based materials may be combined as long as the adhesion is good. The shell 12 needs to be harder than the core 11, but the difference in hardness is 0.01 to 10 as compressive strength when both are particles having the same particle diameter.
kg / mm ² . It is desirable that the shell 12 completely covers the core 11 (100%) from the viewpoints of hardness variation, ease of metal plating described later, and the like. Should cover at least 80%.

When an acrylic resin is used as the core 11, an alkyl group having an alkyl group having a large molecular weight of 4 to 18 carbon atoms (alkyl group) or 4 carbon atoms (alkyl group) is used for imparting flexibility. To methacrylic acid esters of -18 to 18, which are cross-linked by multifunctional monomers such as ethylene glycol dimethacrylate, 1,3 butylene glycol dimethacrylate, neopentyl glycol dimethacrylate, diethylene glycol dimethacrylate, Monomers such as trimethylolpropane trimethacrylate, allyl glycidyl ether, N-methylol methacrylamide, and diallyl phthalate are used. Further, in order to adjust flexibility, vinyl chloride, vinyl acetate, butadiene rubber, acrylonitrile and the like may be copolymerized. The polymerization can be carried out by a conventionally known method, and particularly preferably a suspension polymerization. When an acrylic resin is used, the shell 12 constituting the present invention has a small carbon number (alkyl group) of 1 to 1 in molecular weight of the alkyl group so as to be hard on the core surface.
7 acrylate, carbon number (alkyl group) 1 to 7
The above-mentioned copolymers may be appropriately mixed using methacrylic acid ester or the like, which is obtained by performing a polymerization reaction to form a shell on the core surface.

Next, the weight ratio between the core 11 and the shell 12 has a great influence on the compressive strength and the recovery rate, which will be described later. Set to weight ratio. If the weight ratio of the shell 11 / nucleus 12 is out of the above range, it will be difficult to adjust the compressive strength and the recovery rate, which will be described later, by selecting the above materials. That is,
When the weight ratio of shell / core is less than 1/10, it is difficult to have a restoration rate as the performance of the shell.
If it exceeds 1, it becomes difficult to develop a compressive strength as a performance of the core. The core 11 described above usually has a compressive strength of more than 0 to 3 kg / mm ² alone, and more than 0 to 40%
With a restoration rate. By forming a shell harder than the nucleus by the material of the shell 12 and the polymerization reaction on the nucleus 11, synthetic resin particles having almost the same compressive strength and recovery rate as the intended conductive particles can be obtained. . In other words, the synthetic resin-based particles are subjected to metal plating on the surface as described below. However, the compressive strength and the recovery rate are not significantly changed by this metal plating.
Since it is about 0.3 kg / mm ² and the recovery rate is about ± 3%, the nucleus may be formed in consideration of these.

A metal plating 13 is applied to the surface of the thus-produced synthetic resin-based particles in order to provide conductivity. In order to obtain a good connection, the outermost surface is preferably made of noble metal plating, for example, Ni / Au, Ni / P
d, noble metal plating of a two-layer structure such as Ag / Au.
This plating method can also be formed by using a conventionally known electroless plating method or the like. As plating thickness,
Ni, Ag, etc. for the inner layer (first layer) is 0.05 to 0.3 μm
m, and Au, Pt,
It is preferable that the precious metal such as Pd has a thickness of 50 to 500 angstroms. The specific gravity of the conductive particles thus obtained is about 1.0 to 3.0.

The average particle diameter (φ) of the conductive particles 1 thus obtained depends on the terminal pitch of the substrate to be connected.
Usually, it is in the range of 1 to 50 μm. As the terminal pitch of the substrate becomes smaller, the connection reliability and line-to-line insulation resistance cannot be compatible unless conductive particles having a smaller average particle size are used. Further, the particle diameter is desirably as uniform as possible, and more preferably 40% or less as the CV value. The “average particle size” defined in the present invention indicates an average particle size in a weight distribution measured by a commercially available Coulter counter (particle size distribution measuring device), and the CV value is (standard deviation / average particle size). ) × 100. In the present invention, the conductive particles may be spherical or flat spheres, but the flattening ratio (short axis / long axis) is 0.6 or more, preferably 0.8 or more. However, it is desirable from the viewpoint of connection reliability.

The 10% compressive strength of the conductive particles is as follows:
0.2-5.0 kg / mm ² , preferably 0.5-3.5 k
g / mm ^2, and as described later, if the 10% compressive strength is less than 0.2 kg / mm ² due to the thickness of the insulating resin and the entanglement with the melt viscosity, it is easily deformed too much. However, there is a possibility that the coating of the insulating resin covering the periphery of the conductive particles may not be broken through, the connection may be unstable, and if the 10% compressive strength exceeds 5 kg / mm ² , as described above, There is a possibility that the surface contact with the adherend may be difficult, and the contact may be close to the point contact, which may result in a lack of long-term connection reliability. It should be noted that “1” defined in the present invention
"0% compressive strength" indicates the strength when the particle size of the conductive particles is displaced by 10% when a commonly used microcompression tester (Shimadzu Corporation: MCTM-500 or the like) is used.

Further, the restoration rate of the conductive particles is 5 to 90.
%, Preferably 10 to 60%.
If the recovery rate is less than 5%, the deformation is close to plastic deformation, and the contact pressure required for connection may not be kept high. If the recovery rate exceeds 90%, it is difficult to manufacture due to the relationship with the compressive strength. It may be. The "restoration rate" defined in the present invention is measured by the above-mentioned micro-compression tester, and the load is removed from the point where a load of 1 g is applied, and the degree to which the displacement returns is indicated by "%". It is a thing. More specifically, when a load is applied to the conductive particles using a micro-compression tester, the load-compression displacement relationship increases as the relationship increases, as shown in FIG. Removing the load at the point returns the displacement. At this time,% of the restoration amount b with respect to the compression amount a, that is, (b / a) × 100 is the restoration ratio (%).

Further, in the present invention, the insulating resin 2 is coated around the conductive particles 1. As the material of the insulating resin 2, a thermoplastic or thermosetting resin which flows by heating is used. . Specifically, ethylene-vinyl acetate copolymer, carboxyl-modified ethylene-vinyl acetate copolymer, ethylene-isobutyl acrylate copolymer, polyamide, polyester, polymethyl methacrylate, polyvinyl ether, polyvinyl butyral, polyurethane, styrene-butylene -Styrene (SBS)
Copolymer, carboxyl-modified SBS copolymer, styrene-isoprene-styrene (SIS) copolymer, styrene-ethylene-butylene-styrene (SEBS) copolymer, maleic acid-modified SBES copolymer, polybutadiene rubber, One selected from chloroprene sulfur rubber (CR), styrene-butadiene rubber, isobutylene-isoprene copolymer, unvulcanized acrylonitrile-butadiene rubber (NBR), solid epoxy resin, t-butylphenol resin, p-vinylphenol resin, etc. Alternatively, those prepared by using a compound obtained by a combination of two or more kinds as a main agent are exemplified. As a method for coating these insulating resins around the conductive particles, conventional methods can be used, for example, a chemical method using an emulsion or a chemical reaction (in-situ polymerization method, interface reaction method, etc.).
And a mechanofusion method using a mechanical force, a mechanochemical method, and the like.

The following formula (I) is defined between the average thickness (T) of the insulating resin and the average particle diameter (φ) of the conductive particles.
It is preferable to have the following relationship. φ ≧ 2T (I) By having φ ≧ 2T, conduction can be further stabilized. The above formula (I)
In this case, when φ <2T, the possibility of unstable conduction increases, which is not preferable. Further, the average thickness (T) of the insulating resin depends on the average particle diameter of the conductive particles, but is appropriately experimentally selected from the range of usually 0.1 to 25 μm. It is desirable that the insulating resin completely (100%) cover the conductive particles, but the coating ratio covers 60% or more, preferably 80% or more of the surface of the conductive particles. It is practically sufficient.

As described above, the conductivity-imparting particles of the present invention thus constituted have a surface of a synthetic resin-based particle comprising a core having flexibility and a shell covering the core which is harder than the core. In addition, the surface of the conductive particles coated with metal is coated with an insulating resin, thereby increasing the contact area with a flexible core and the restoration rate with a hard shell. In addition, since the insulating property can be maintained by the insulating film, the reliability of the electrical connection can be improved in the temperature / humidity cycle and the thermal shock, and the insulating property can be improved.

Further, the anisotropic conductive adhesive of the present invention is characterized in that the conductive particles having the above-mentioned structure are dispersed in an insulating adhesive. The insulating adhesive constituting the anisotropic conductive adhesive may be a commonly used insulating adhesive, and may be either thermoplastic or thermosetting as long as it exhibits adhesiveness when heated. Specifically, ethylene-vinyl acetate copolymer, carboxyl-modified ethylene-vinyl acetate copolymer, ethylene-isobutyl acrylate copolymer, polyamide, polyester, polymethyl methacrylate, polyvinyl ether, polyvinyl butyral, polyurethane, styrene-butylene -Styrene (SBS) copolymer, carboxyl-modified SBS copolymer, styrene-isoprene-styrene (SIS) copolymer, styrene-ethylene-butylene-styrene (SEB)
S) Copolymer, maleic acid modified SBES copolymer, polybutadiene rubber, chloroprene rubber (CR), carboxyl modified CR, styrene-butadiene rubber, isobutylene-isoprene copolymer, acrylonitrile-butadiene rubber (NBR), carboxyl-modified NBR And those prepared by using, as a main component, one obtained by one or a combination of two or more selected from amine-modified NBR, epoxy resin, phenol resin, silicone rubber, acrylic rubber and the like. In addition, when using a thermosetting resin, it is usually preferable that the resin is uncured before the thermocompression bonding, but even if the resin is cured before the thermocompression bonding, the distance between the crosslinking points is large. Then, it is necessary to add a large amount of additives such as a tackifier as described below between the molecules so that the entire adhesive has a melting point of a melting point to impart adhesiveness.

This insulating adhesive includes the above-mentioned main ingredient,
One or two of rosin as a tackifier, rosin derivative, terpene resin, terpene phenol resin, petroleum resin, cumarone-indene resin, styrene resin, isoprene resin, alkylphenol resin, xylene resin, etc.
At least one kind; a reactive auxiliary; a polyol as a crosslinking agent, an isocyanate, a melamine resin, a urea resin, an utropine, an amine, an acid anhydride, a peroxide, a metal oxide, and a chromium trifluoroacetate salt. Salts, alkoxides such as titanium, zirconia and aluminum, organometallic compounds such as dibutyltin dioxide; photoinitiators such as 2,2-diethoxyacetophenone and benzyl; sensitizers such as amines, phosphorus compounds and chlorine compounds Is optional, and may also include a curing agent, a vulcanizing agent, a deterioration inhibitor, a heat-resistant additive, a heat conduction improver, a softener, a coloring agent, various coupling agents, a metal deactivator, and the like. May be appropriately added.

The anisotropic conductive adhesive of the present invention can be obtained by dispersing and mixing the above-mentioned conductive particles in the above-mentioned insulating adhesive according to a conventional method. The amount of the conductive particles is 0.01 to 100 parts by volume, preferably 1 to 10 parts by volume, based on 100 parts by volume of the insulating adhesive. The compounding amount of the conductivity imparting particles is 0.01
If it is less than the capacitance part, conduction failure is likely to occur, and conversely, 1
If the capacity exceeds 00 capacity, insulation failure is likely to occur.
In addition, this insulating adhesive, when the adhesive and adhesive components are solid at room temperature, or when a high-viscosity liquid, this is an ester-based,
Dissolved in ketone, ether ester, ether, alcohol, and hydrocarbon solvents such as ethyl acetate, methyl ethyl ketone, butyl cellosolve, ethyl carbitol, diisoamyl ether, cyclohexanol, petroleum spirit, and toluene The solution may be applied to a desired position on the electrode to be connected by an appropriate printing method or a coating method.After forming on the separator, the solution is cut into a desired size, and then the connection electrode is formed. When the adhesive or tacky component is in a liquid state, it can be used by applying it to a connection electrode during connection work.

Further, the melting point (M ₁ ) of the insulating resin 2
Is an insulating adhesive 3 as a matrix (see FIG. 3)
Melting point (M ₂₎ a temperature lower than (M ₁ <M ₂₎ is, and the melt viscosity of the insulating resin 2 in the melting point (M ₂₎ of the insulating adhesive .rho.1 (poise hereinafter, simply "poise" ) And the melt viscosity ρ2 (poise) of the insulating adhesive preferably have the relationship of the following formula (II). (Ρ1−ρ2) ≦ 12000 (poise) (II) By having the relationship of the above formula (II), by applying a pressure of 10 to 60 kg / cm ² from above and below the conductive particles during thermocompression bonding. The adhesive melts and adheres after the surface of the conductive particles has appeared with certainty, so that conduction can be easily obtained. When ρ1−ρ2> 12000, the possibility that the surface of the conductive particles hardly appears becomes high, which is not preferable.

The anisotropic conductive adhesive B of the present invention thus obtained is, for example, as shown in FIG. 3, a flexible core 11 and a harder core than the core 11 covering the core 11. The conductive imparting particles A composed of the shell 12, the metal plating 13 on the surface, and the insulating resin 2 around the shell 12 are bonded to the insulating adhesive 3.
Anisotropic conductive adhesive B dispersed in LCD substrate 4
And the flexible printed circuit board 5. Reference numeral 6 denotes a conductor (circuit). The anisotropic conductive adhesive is generally interposed between two opposing electrons, electrodes on an electric circuit board, etc., and is pressed from above one of the electrons, the electric circuit board, etc., and simultaneously heated, or irradiated with light or electron beam. To activate the adhesive, fix the two circuit boards and the like with the anisotropic conductive adhesive, and electrically connect the opposing electrodes via the conductivity imparting particles. As the circuit board, for example, glass such as a display panel, L
A flexible printed circuit based on a metal such as an SI chip, a metal oxide, a polyimide resin, a polyester resin, or the like is used. Note that the conductivity-imparting particles that do not contribute to the connection, that is, the conductive particles that are not sandwiched between the opposing electrodes are practically covered with the insulating resin 2 and thus do not cause a short circuit (leak). .

[0023]

The present invention will be described below in more detail with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples. The 10% compressive strength and the restoring rate in the examples and comparative examples were measured using a micro compression tester (MCTM-500, manufactured by Shimadzu Corporation). The measurement was performed under the conditions of a load of 50.00 gf, a displacement full scale of 50 μm, an indenter plane of 50 μmφ, and a load speed of 1.975 gf / sec. The restoration rate was set in test mode 2 (load, unloading test), and the reverse load value was 1.00 gf. The measurement was performed under the conditions of a load speed of 0.455 gf / sec, a displacement full scale of 50 μm, an indenter plane of 50 μmφ, and a load value for the origin of 0.10 gf.

[Production Example 1: Production of Conductivity-imparting Particles] 100 parts by weight of stearyl acrylate, 4 parts by weight of ethylene glycol dimethacrylate, 30 parts by weight of butadiene rubber, and 0.5 parts by weight of benzoyl peroxide were mixed with 200 parts of water. Suspension polymerization was carried out for 2 hours at 100 ° C. and 1000 rpm in a weight part to obtain a suspension containing a core having an average particle diameter of 7 μm and a CV value of 28%. Where this core was measured small amounts up compression strength and recovery rate, compressive strength 0.8 kg / mm ^2, restoration rate of 3%
Met. Further, 50 parts by weight of ethyl methacrylate and 2 parts by weight of ethylene glycol dimethacrylate were added to the suspension while stirring, and the suspension was stirred at 90 ° C. under 1,000 rpm.
A shell was formed on the surface by polymerization for a time, and then cooled, washed with water and dried to obtain acrylic resin particles having an average particle diameter of 10 μm and a CV value of 35%. When a small amount of the acrylic resin particles were taken and the compressive strength and the recovery rate were measured, the compressive strength was 2.1 kg / mm ² ,
The restoration rate was 50%. Next, electroless plating is performed on the surface of the particles in the order of nickel plating 0.3 μm and gold plating 0.02 μm to form conductive particles [average particle diameter (φ) 10.
32 μm, CV value 35%]. 1 of this conductive particle
The 0% compressive strength was 2.2 kg / mm ² , the restoration rate was 50.1%, and the specific gravity was 2.27. Further, the melting point (M ₁ ) at 110 ° C. and the melt viscosity at 150 ° C. (ρ1) 1 around the above-mentioned conductive particles by mechanofusion method.
A 000 poise thermoplastic solid epoxy resin (insulating resin) was coated to an average thickness (T) of 2 μm to obtain conductive particles.

Example 1: Preparation of anisotropic conductive adhesive (1) Preparation of insulating adhesive solution 100 parts by weight of NBR, epoxy equivalent of 1000 to 1200
150 parts by weight of bisphenol type epoxy resin, 20 parts by weight of 2-methylimidazole, titanium oxide (TiO ₂ )
To 50 parts by weight, 300 parts by weight of cyclohexanone was added and dissolved to prepare an insulating adhesive solution. The melting point (M ₂ ) of the insulating adhesive obtained by drying the insulating adhesive solution was 150 ° C., and the melt viscosity (ρ
2) was 480000 poise.

(2) Preparation of Anisotropic Conductive Adhesive 10 parts by volume of the conductivity-imparting particles prepared in Production Example 1 were added to 100 parts by volume of the solid content of the insulating adhesive solution prepared in (1) above. An anisotropic conductive adhesive was produced.

(3) Preparation of Flexible Printed Circuit Board (FPC) with Anisotropic Conductive Adhesive A commercially available silver paste (DW-250H-5, Toyo) was placed on a flexible substrate made of a PET film having a thickness of 25 μm. Spinning) is printed by screen printing to form conductive lines with a pitch of 0.15 mm, and then 5
Dry for a time and cure. Next, an anisotropic conductive adhesive layer is formed by screen printing so that the thickness of the connection terminal portion after removing the solvent of the anisotropic conductive adhesive prepared above becomes 9 μm, A commercially available insulating resist (JEH-112, manufactured by Acheson Japan) was provided on the remaining portion, and this was cut into desired dimensions to obtain an FPC with an anisotropic conductive adhesive. Next, the thus obtained F with anisotropic conductive adhesive
PC was used as a transparent conductive oxide film substrate (I
160 ° C, 30 kgf / cm between connection terminal of TO) and FPC
² , thermocompression bonding for 12 seconds, under high temperature (110 ℃) ・ 3
100 minutes of environmental tests from 0 minutes to low temperature (-20 ° C) for 30 minutes
When the resistance value (Ω) between both connection terminals and the insulation resistance (MΩ) between the terminals were measured by performing 0 cycles, the results shown in Tables 1 and 2 below were obtained.

[Comparative Example 1] As conductive particles, conductive particles obtained by plating single-component styrene resin particles with Ni and Au (10% compressive strength 12 kg / mm ² , recovery rate 49%, average particle diameter 10) .32 μm, CV value 35%, specific gravity 1.75)
A FPC with an anisotropic conductive adhesive was obtained in the same manner as in Example 1 except that was used. When the resistance value (Ω) between both connection terminals and the insulation resistance (MΩ) between the terminals were measured in the same manner as in Example 1, the results shown in Tables 1 and 2 below were obtained.

Comparative Example 2 Conductive particles obtained by plating Ni and Au on single-component acrylic rubber particles as the conductive particles (10% compressive strength: 1 kg / mm ² , restoration rate: 3%, average particle diameter: 10%). 32 μm, a CV value of 45%, and a specific gravity of 1.72), except that F with an anisotropic conductive adhesive was used.
PC was obtained. When the resistance value (Ω) between both connection terminals and the insulation resistance (MΩ) between the terminals were measured in the same manner as in Example 1, the results shown in Tables 1 and 2 below were obtained.

[0030]

[Table 1]

[0031]

[Table 2]

(Consideration of Tables 1 and 2) The above Tables 1 and 2
As is clear from the results of Example 1, Example 1 within the scope of the present invention
Shows that the initial connection resistance is lower than that of Comparative Examples 1 and 2 which are out of the scope of the present invention, and that the environmental test is performed at a high temperature (110 ° C.) for 30 minutes to a low temperature (-20 ° C.) for 30 minutes The resistance value between the connection terminals (Ω) and the insulation resistance between the terminals (MΩ) do not change even if the process is performed for 1000 cycles, and the anisotropic conductivity that is excellent in long-term connection reliability and maintains insulation. It was found to be an adhesive.

Further, Examples 2 and 3 according to the present invention will be described below. [Example 2] A nucleus having a compressive strength of 0.2 kg / mm ² , a restoration rate of 2%,
SBS resin having an average particle diameter of 7 μm and a CV value of 30%, and a shell made of styrene resin, having an average particle diameter of 10 μm and a CV value of 33%;
When an environmental test was performed in the same manner as in Example 1 except that resin particles having a compressive strength of 0.25 kg / mm ² and a restoration rate of 25% were used, good results were obtained as in Example 1.

Example 3 Epoxy equivalent 230 to 270
100 parts by weight of an epoxy resin having a molecular weight of 15,000 to 17
000 saturated polyester resin, 50 parts by weight of a latent curing agent (Sun-Aid SI-60: product name)
50 parts by weight of EK-toluene = 1: 1 solvent was added to obtain an insulating adhesive. The melting point of the insulating adhesive obtained by drying this insulating adhesive was 120 ° C., and the melt viscosity at that time was 480,000 poise. When an environmental test was performed in the same manner as in Example 1 except that this insulating adhesive was used, good results were obtained as in Example 1.

[0035]

According to the first and second aspects of the present invention, the contact area is increased by the flexible core, the restoration ratio is provided by the harder shell, and the unnecessary portion is provided by the insulating resin film. Since short circuit (leak) can be prevented, the reliability of electrical connection is improved in temperature / humidity cycle and thermal shock, and the leak prevention is excellent.
Provided are conductive particles suitable for anisotropic conductive adhesives. According to the third aspect of the present invention, since the conductivity imparting particles have flexibility and can maintain a high restoring force, the initial connection resistance is low, the reliability of the connection for a long time is excellent, and the insulation property is high. Is provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of an embodiment of a conductivity imparting particle of the present invention.

FIG. 2 is an explanatory diagram for explaining a restoration rate.

FIG. 3 is a longitudinal sectional view showing one usage example of the anisotropic conductive adhesive of the present invention.

[Explanation of symbols]

 A Conductivity imparting particles B Anisotropic conductive adhesive 1 Conductive particles 11 Nucleus 12 Shell 13 Metal plating 2 Insulating resin (film) 3 Insulating adhesive 4 LCD substrate 5 FPC

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01R 11/01 H01R 11/01 J F term (Reference) 4J040 CA052 CA152 DA052 DA062 DB012 DB032 DD052 DD072 DE032 DF042 DF052 DM002 DM012 EB032 EB042 EB132 ED002 EF002 EG002 EK032 HA066 HA076 JB10 KA03 KA07 KA32 LA08 LA09 NA20 5G301 DA02 DA42 DA60 DD03

Claims (3)

[Claims] The surface of a synthetic resin-based particle comprising a core having flexibility and a shell harder than the core which covers the core is coated with metal plating to further insulate the surface of the conductive particle. Conductivity imparting particles characterized by being covered with a resin. 2. The conductive particles have a 10% compressive strength of 0.2 to 0.2%.
^2. The conductivity-imparting particles according to claim 1, wherein the conductivity-imparting particles are 5.0 kg / mm ² and the restoration rate is 5 to 90%. 3. An anisotropic conductive adhesive characterized by dispersing the conductive particles according to claim 1 or 2 in an insulating adhesive.